1. Field of Invention
The present invention relates to a drive device for driving a member to rotate using a vibration actuator. The present invention also relates to an information recording and processing device for performing reading and/or writing of information by causing an information recording medium to rotate using the drive device.
2. Description of Related Art
In the past, when rotatably driving a disk such as a turntable using a vibration actuator, a disk shaped vibration actuator that rotated was used.
This vibration actuator is provided at least with a disk (rotor) and an elastic member (stator) for driving the disk to rotate. A piezoelectric element caused vibration in the elastic member, and a pressing member pressed the disk into contact with the elastic member. These constituent elements are stacked in sequence in the direction of the axis of rotation of the disk.
However, in this type of structure, because the disk, elastic member, piezoelectric element, and pressing member, and the like, are stacked in sequence in the direction of the axis of rotation of the disk, the space in the direction of the axis of rotation of the disk must be made large. Therefore, when the vibration actuator is incorporated into an information recording and processing device (e.g., a disk drive), it becomes difficult to make the size of this processing device compact in the direction of the aforementioned axis of rotation.
Also, because the disk is pressed in the direction of the axis of rotation by the pressing member, its position may change in the direction of pressing (i.e., as the pressing member is compressed or expanded in the pressing direction). Therefore, there is the possibility that the depth of focusing of the head for reading/writing the information by projecting a light beam on the surface of the disk may change.